The invention relates to a belt grinding machine with a pressure bar which has a plurality of pressure shoes arranged next to one another transversely relative to the conveying direction of the work-piece to be machined, and in which each pressure shoe has assigned to it its own pressing-on device actuable as a function of workpiece parameters, the pressing-on force of the pressing-on device being controlled by means of a signal-processing unit taking into account the workpiece parameters and local and time data of the workpiece transport operation.
A belt grinding machine of this type is known from German Patent Specification 3,402,104. It affords the advantage that the pressing-on force of the individual pressure shoes can be regulated individually as a function of the workpiece shape. This presupposes a sheet-like workpiece, its shape being determined by the outer limitation of the sheet-like workpiece. The purpose of regulating the pressing-on force is to prevent excessive grinding of the edges of the workpiece. After the work-piece shape has been detected, the appropriate pressure shoes located in the region of the edge are pressed against the workpiece with a decreasing pressing-on force from the center of the workpiece towards the edge, so that the undesirable round grinding of the edges is effectively prevented. The known belt grinding machine is also capable of taking into account variations in thickness of different workpieces at the same machine setting. For this, upstream of the sensing rollers for the workpiece shape detection, a thickness measuring device is arranged which measures the thickness of the workpiece at one place, so that the thickness of the workpiece can be taken into account by the pressing-on force control.